Initializing an array inside of a structure

Hello,

I have been tried to do this but I keep getting segmentation faults.

Code:

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typedef struct
{
  int *v;
  int x;
} st;

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If I declare on main() a pointer to st, like st *s, how can I acess both variables in st?

To access the regular int, I did it this way: s->x=...

How to declare v with n elements, using malloc?

Thank you.

You have to allocate memory for the struct before you allocate memory for v.

Code:

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st s;
s.n = 100;
s.v = malloc(sizeof(your_type) * s.n);

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but this declaration :
s.v = malloc(sizeof(your_type) * s.n);
malloc fn. return a void pointer so u have to make a cast type by writing
s.v=(int *)malloc(sizeof(your_type) * s.n);

Not in C. In C++ you do, but in C++, you use new instead of malloc.

Quote:

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Originally Posted by mostafa faisal

malloc fn. return a void pointer so u have to make a cast type by writing
s.v=(int *)malloc(sizeof(your_type) * s.n);

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Pointers to void are implicitly convertible to pointers to object types, hence the cast is unnecessary.

If your compiler complains about the lack of cast for malloc(), either one of the following issues have occured:

1. You forgot to #include <stdlib.h>
2. Your compiler is compiling as C++.